Is Nintendo Making A Motion Sensing DS Card?

Maybe! A Nintendo trademark that's appeared on the Japanese trademark database indicates such.

The trademark is for a "DS Houi Sensor Card" with "houi" meaning "direction" or even "cardinal point" in Japanese. Website Siliconera wonders if that means it refers to the ability to sense motion or detect direction. (Maybe Nintendo is making some sort of compass game?)

This isn't the first time DS has seen motion controls — first party peripheral add-on/game combo Slide Adventure: MAGKID came out last year.